Exemplary embodiments relate to a three-dimensional semiconductor memory device, and in particular, to a highly-reliable, highly-integrated three-dimensional semiconductor memory device.
Higher integration of semiconductor devices is required to satisfy consumer demands for superior performance and inexpensive prices. In the case of semiconductor devices, since their integration is an important factor in determining product prices, increased integration is especially important. In the case of conventional two-dimensional or planar semiconductor devices, since their integration is mainly determined by the area occupied by a unit memory cell, integration is greatly influenced by the level of a fine pattern forming technology. However, the extremely expensive process equipment needed to increase pattern fineness sets a practical limitation on increasing integration for two-dimensional or planar semiconductor devices. To overcome such a limitation, there have been recently proposed three-dimensional semiconductor memory devices that include three-dimensionally arranged memory cells.